A conventional optical connector is obtained by forming an optical fiber insertion hole which penetrates between a rear end of a ferrule and a connection end surface which is a front end of the ferrule, thereafter inserting an optical fiber through the optical fiber insertion hole from the rear end side toward a tip, thereafter fixedly bonding the optical fiber and the ferrule using a heat-hardening adhesive which contains an epoxy or the like, and thereafter grinding the connection end surface together with a tip surface of the optical fiber.
When this type of optical connectors are to be connected to each other, connection end surfaces of one optical connector and the other optical connector are abutted against each other after aligning the optical connectors to each other in such a manner that an optical fiber of one optical connector is abutted against an optical fiber of the other optical connector without any positional displacement, whereby the optical fibers are connected to each other through the connectors.
Since connection of optical fibers to each other using this type of optical connectors is a method of connecting optical fibers to each other which requires to abut connection end surfaces of the optical connectors against each other, if a small gap is created between the optical fiber of one of the optical connectors and the optical fiber of the other one of the optical connectors, reflection of light or the like is created at the gap, which increases a connection loss. To deal with this, when optical connectors are to be connected to each other, a matching agent (matching oil) is applied to connection end surfaces of the optical connectors so that an inconvenience such as reflection of light is prevented when the optical connectors are connected to each other.
However, applying a matching agent every time optical connectors are connected to each other is very much burdensome, and therefore, it is impossible to enhance the operability of connecting optical connectors to each other. Against the backdrop, recent years have seen an increased use of optical connectors of a physical contact type which allows optical fibers to be connected to each other without using a matching agent. An optical connector of the physical contact type is manufactured by grinding a connection end surface of a ferrule using a buff after inserting an optical fiber through the ferrule and fixing the optical fiber therein. Buff grinding is performed utilizing a fact that the ferrule whose hardness is small is chipped off more than the optical fiber whose hardness is large, thereby allowing the optical fiber to project a little longer from the connection end surface of the ferrule.
When optical fibers are to be connected to each other using optical connectors of the physical contact type, connection end surfaces of the connectors are abutted against each other and the optical fibers of the optical connectors which project a little longer from the connection end surfaces are accordingly brought into a direct pressure contact with each other so that reflection of light or the like at this contact portion is prevented, which in turn makes it possible to connect the optical fibers to each other without using a matching agent and hence with only a small connection loss.
An optical connector mounting an optical fiber cored line may contain only one line. However, with a recent tendency toward optical communication with a large capacity, a ferrule mounting containing more than one optical fibers of cable conductors is in a popular use.
During fabrication of a multi-cored optical connector of the physical contact type, in particular, when a connection end surface of a ferrule in which multi-cored optical fibers are arranged is ground using a buff in an effort to allow tips of the optical fibers to project from the end surface of the ferrule as conventionally performed, since the buff is soft, as it is known in the art, the buff chips off different quantities at different positions, so that the multi-cored optical fibers are ground away different quantities and projection lengths of the optical fibers accordingly become different from each other. This degrades the performance of connecting the multi-cored optical fibers and makes it impossible to perform reliable connection of the optical fibers.
The present invention has been made to solve such a problem. Accordingly, an object of the present invention is to obtain a method of manufacturing an optical connector which, even if an optical connector is a multi-cored optical connector, allows optical fibers each containing a cored-line to project evenly from a connection end surface and adjusts the projection so that the quantities of the projection are optimum.